[patch] Add --compress-debug-sections option to gas

[Cary Coutant]

> Good, although the documentation still does not mention that
> --compress-debug-sections may not be supported.  How about:
>
>  @item --compress-debug-sections
>  Compress DWARF debug sections using zlib.  The debug sections are renamed
>  to begin with @samp{.zdebug}, and the resulting object file may not be
>  compatible with older linkers and object file utilities.  This option is
>  only supported if the host machine has the zlib compression library.

Sorry, I forgot to incorporate that change into my patch. Is this
patch OK to apply with your suggested change?

-cary